Narrative:

I was repositioning the aircraft from the ramp to taxiway charlie in preparation for takeoff. The ramp was very poorly illuminated and a high overcast made for very dark conditions. Our taxi lights were on and we were moving slowly toward taxiway charlie. The edge of the ramp was not marked with any type of sign; reflector or warning of any kind. I was looking for the taxiway yellow line and before I could complete a turn the nose wheel entered a grassy area. I immediately stopped the aircraft and the recognition light revealed what appeared to be a level area suitable for crossing. The taxi lights of charlie were visible about 50 feet ahead. I added power and the nose dipped down and I continued through the grassy area. There was an unseen dip in the grassy area that was not visible. It caused an up down motion. Because of the motion of the aircraft I decided to do an inspection prior to resuming the mission. I taxied back to the ramp and shut down the engines. The inspection revealed the delta fins had been bent upward on the ends with a hole on the underside of each fin. I grounded the aircraft and tended to the passengers. There were no injuries. I called our director of maintenance and director of operations that evening and informed them of the event. I notified the FSDO duty officer the next morning. The factors leading up to this event were the extremely poor ramp lighting; lack of markings on the edge of the ramp and inadequate taxiway lines from the ramp leading to runway 10. My decision to proceed forward based on the visible surface was ill-advised. Stopping the aircraft and inspecting the surrounding area would have been the appropriate action.

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Original NASA ASRS Text

Title: Lear 60 Flight Crew reports a Ramp excursion at LAF airport while attempting a right turn out of parking during darkness. The lack of signs; lines; or adequate lighting were cited as factors. A decision is made to power through the grass median and the aircraft's Delta fins are damaged in the process.

Narrative: I was repositioning the aircraft from the ramp to Taxiway Charlie in preparation for takeoff. The ramp was very poorly illuminated and a high overcast made for very dark conditions. Our taxi lights were on and we were moving slowly toward taxiway Charlie. The edge of the ramp was not marked with any type of sign; reflector or warning of any kind. I was looking for the taxiway yellow line and before I could complete a turn the nose wheel entered a grassy area. I immediately stopped the aircraft and the recognition light revealed what appeared to be a level area suitable for crossing. The taxi lights of Charlie were visible about 50 feet ahead. I added power and the nose dipped down and I continued through the grassy area. There was an unseen dip in the grassy area that was not visible. It caused an up down motion. Because of the motion of the aircraft I decided to do an inspection prior to resuming the mission. I taxied back to the ramp and shut down the engines. The inspection revealed the delta fins had been bent upward on the ends with a hole on the underside of each fin. I grounded the aircraft and tended to the passengers. There were no injuries. I called our Director of Maintenance and Director of Operations that evening and informed them of the event. I notified the FSDO Duty Officer the next morning. The factors leading up to this event were the extremely poor ramp lighting; lack of markings on the edge of the ramp and inadequate taxiway lines from the ramp leading to Runway 10. My decision to proceed forward based on the visible surface was ill-advised. Stopping the aircraft and inspecting the surrounding area would have been the appropriate action.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.